duete; see due, ty 2 ]. syn: duty, obligation refer to something a person feels bound to do. A duty often applies to what a person performs in fulfillment of the permanent dictates of conscience, piety, right, or law: one's duty to tell the truth; a parent's duty to raise children properly.
Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and keeps cells from dividing too rapidly or in an uncontrolled way.
This form of cancer develops in the retina, which is the specialized light-sensitive tissue at the back of the eye that detects light and color. In most children with retinoblastoma, the disease affects only one eye. However, one out of three children with retinoblastoma develops cancer in both eyes.The most common first sign of retinoblastoma is a visible whiteness in the pupil called cat's eye reflex or leukocoria.n the non-germinal form of retinoblastoma, typically only one eye is affected and there is no family history of the disease. Affected individuals are born with two normal copies of the RB1 gene. Then, usually in early childhood, both copies of the RB1 gene in retinal cells acquire mutations or are lost.